1. Field of the Invention
The present invention relates to an endoscope.
2. Description of the Related Art
At present, a “dye observation method” to disperse various dyes during an endoscopic inspection and observe their reactions and others are considered to be effective in early recognition of lesions, particularly cancer, determination of a lesion range, and assessment of the degree of invasion. There are various kinds of dyes that are characterized by, for example, being different from one another in principle and color. Dyes to be used differ depending on parts and lesions. However, living bodies principally show red-based colors, and a blue dye, which absorbs long-wavelength-side yellow and red components, is often used in order to form a contrast with the red-based colors.
Jpn. Pat. Appln. KOKAI Publication No. 2008-273900 discloses a such dye observation method. According to this literature, it is possible to easily recognize a boundary between a lesion part and a normal part by dispersing an indigo carmine aqueous solution having a density of 0.08 to 0.25 w/v % and an acetic acid aqueous solution having a density of 3.0 to 5.0 w/v % to an observation part at the same time or at an interval of a predetermined time during an endoscopic inspection.